Fluoride intakes of 9-10-year-old children living in fluoridated and non-fluoridated areas of Dunedin and Timaru – A pilot study

Watts, Chontelle

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Watts, C. (2018). Fluoride intakes of 9-10-year-old children living in fluoridated and non-fluoridated areas of Dunedin and Timaru – A pilot study (Thesis, Master of Dietetics). University of Otago. Retrieved from http://hdl.handle.net/10523/7887

Background: Fluoride plays an important role in preventing dental caries, however ingesting too much can cause dental and skeletal fluorosis. Determining the impact of community water fluoridation (CWF) is important as changes in the regulation of CWF in New Zealand are in progress. Previous research has focused on the fluoride intakes of children <8 years, as they are at a higher risk of fluorosis resulting in a lack of data on older children. This pilot study aimed to measure fluoride intakes of 9-10-year-old children living in fluoridated and non-fluoridated regions, while evaluating the methods required to get an accurate estimate.

Objectives: To evaluate the use of diet records and duplicate diets to determine fluoride intake from dietary sources, including fluoridated water; to evaluate the collection method of expectorated toothpaste to determine fluoride intake from toothpaste ingestion, and to evaluate the feasibility of 24-hour urinary collections to determine urinary fluoride excretion.

Design: Fluoride intakes were estimated for 10 children from Dunedin (fluoridated water) and 10 from Timaru (non-fluoridated water). Data collection involved 24-hour duplicate diets, 24-hour diet records, 24-hour urine samples, estimation of toothpaste ingestion and toenail samples. Children completed either one or two days of data collection on weekend days or in the school holidays.

Results: The mean total daily fluoride intake was 1.66 ± 0.56mg/d and 1.20 ± 0.60mg/d in Dunedin and Timaru, respectively, below the adequate intake of 2.0mg/d. No participant exceeded the upper limit of 10mg/d. The mean fluoride intake from diet alone, was 0.71 ± 0.36mg/d in Dunedin and 0.21 ± 0.06mg/d in Timaru, with toothpaste contributing an additional 0.95 ± 0.41mg/d and 0.99 ± 0.52mg/d, respectively. Water was the most common source of dietary fluoride intake, contributing 75% and 38% of total dietary fluoride intake in Dunedin and Timaru, followed by breads and cereals, at 15% and 35%, respectively. The daily urinary fluoride excretion was 0.378 ± 0.115mg/d in Dunedin and 0.249 ± 0.122mg/d in Timaru, which equates to 23% and 21% of total daily fluoride intake, respectively. Parents reported the methods to be acceptable, with the majority of children not changing eating habits during the study or changing drinking habits to avoid using the toilet. The results of the duplicate diets and toenails are not presented in this thesis.

Conclusions: Fluoride intake from toothpaste ingestion was the biggest contributor to total daily fluoride intake, providing approximately 50% of the adequate intake in both cities. The effect of CWF in Dunedin was evident, with Dunedin children consuming more fluoride from dietary sources, namely water. The children in both Dunedin and Timaru are at low risk of dental fluorosis, as the upper limit was not exceeded, and consequently may be at higher risk of dental caries. The methods used in this study are feasible and with refinement would be suitable to include in a larger scale study.